def is_root(x):
    x2 = x ** 2
    y = x2 - 2 * x - 3 * (x2 - 2 * x - 3)
    if 0 == y:
        return True
    else:
        return False


def input_and_judge():
    x = float(input('输入数字： '))
    r = is_root(x)
    if r:
        print('%f是方程的根' % x, flush=True);
    else:
        print('%f不是方程的根' % x, flush=True);


for i in range(0, 5):
    input_and_judge()